Method of mixing asphalt.



.1. H. BLEDSOE.

METHOD 0F WHXING ASPHALT.

APPLICATION FILED sanza. 1912.

Lww. Patented Apr. 2o, 31915.

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@JMW/gm' Il OHNEV J. H. BLEDSOE.

METHOD 0F MIXING ASPHALT.

APPLICATION FILED SEPT. 26, |912.

Patented Apr. 20, 1915.

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WTNESSES:

J. H. BLEDSOE.

METHOD 0F MIXING ASPHALT.

APPLICATION FILED SEPT. 26. 1912.

Patented Apr. 20, 1915.

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J. H.'BLEDSOE.

METHOD or Mlxme ASPHALT.

y APPLICATION FILED SEPT-26, i912. J f Patented A111220, 1915.

5 SHEETS-SHEET 4.

J. H. BLEDSOE.

METHOD 0F MIXING ASPHALT.

APPLICATloN FILED SEPT. 2s, 1912. L@ @U5 Patented Apr. 20, 1915.

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JOI-IN H. 1SLIEDSOE, OF KANSAS CITY, MISSOURI, ASSIGNOR T EQUITABLEASPHALT MAINTENANCE COMPANY, OF KANSAS CITY, MISSOURI, A CORPORATION OFMIS- SOURI.

METHOD 0F MIXING ASPHALT.

Specification of Letters Patent.

Patented Apr. 2U, 1915.

To ai? /r/zom. 1' t may concern:

De it known that I, JOHN H. BLnDsoE, a citizen of the United States,residing at Kansas City, in the county of Jackson and State of Missouri,have invented certain new and useful Improvements in Methods of MixingAsphalt; and I do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, and to the letters and figures ofreference marked thereon, which forma part of this specification.

My invention relates toa method of mixing asphalt, and has for itsprincipal object to provide a method whereby asphalt may be thorougl'ilyand efficiently mixed with a mineral aggregate to secure an efficientpaving composition. ing this object I prefer to first heat the mineralaggregate by directing a blast of heated air through the aggregate Whilethe latter is cascaded within a suitable mixing drum, continue the hotblast and cascade after the aggregate has been heated and dried, andintroduce the asphalt in a fluid jet through the cascade, varying thepressure of the iet during the mixing operation in order to vary thepenetration of the jet into the cascade and thereby distribute the iuidevenly throughout the shower of the hot mineral aggregate. I preferablyperform the cascading operation by means of a revoluble drum havinginterior blades whereby the material is lifted to the upper portion ofthe drum and then dropped through the interior thereof so that the airblast and jet of asphalt may be delivered therethrough and the completecomposition thoroughly mixed following the introduction of the asphalt.By providing a blast of heated air, I secure the drying and heatingeffect without llame and thereby eliminate the danger of scorching theasphalt or overheating same to such an extent that the bitumen thereinis destroyed.

In cari-ying out my method I have provided an apparatus, the preferredform of which is illustrated in the accompanying drawings, wherein lFigure I is a plan view of the apparatus, the parts of which are inassembled relation. Fig. II is a side elevation of the mixing Inaccomplishs drum and material and blast conduits. Fig. III is anenlargedvertical section of the mixing drum, the delivery chute being shown ininoperative position in dotted lines. Fig. IV is a cross-section of thedrum on the line IV-IV, Fig. III. Fig. V is a perspective view of partofthe mixing drum, showing the plate for covering the opening in the innerhead, and parts of the feeding conduits. Fig. VI is a detail view of oneof the mixing blades. Fig. VII is a detail view of the asphalt measuringtank. Fig. VIII is a vertical section of same. Fig. IX is a detail viewof part of the measuring tank,

showing the means for delivering asphalt thereto from the meltingkettle.

While it is possible that my methodmight be carried out with otherapparatus, I will describe the present structure with suiicient detailto illustrate the present structure and the use of my method therewith,With the understanding that I ain not limited to this specificstructure.

l'ieferring more in detail to the drawings, l designates a supportingframe upon which the mixing drum 2, blast oven 3, boiler 4 and fuel tank5 are preferably carried, such fra-me being usually mounted on suitablerunning gear to render the plant or apparatus portable.

An asphalt melting kettle 6 is preferably carried on a separate truckand a measuring tank 7 made detachable from the rest of the apparatus sothat it may be carried by one of the trucks and easily connected Withthe i supply and feed conduits.

The mixing drum 2 preferably comprises a cylindrical structure havingperipheral rails 8 mounted on flanged rollers 9 which are carried byshafts 10 having journaled bearings in standards 11 on the truckframe 1. The drum is also provided With a peripheral rack 12 whichmeshes with a pinion 13 fixed on one of the shafts 10. and having gearconnection 14: with a shaft 15 that is driven from the engine 16. Theouter end of the drum has a head `18 fixed ,thereto andI provided with acentral opening 19 through which the inner end of a swinging deliverychute 20 is adapted to project, the innenend of the drum having a head21 provided with a central opening 22 throughwhich the mineralaggregate, blast and liquid asphalt supply conduits are adapted todeliver, as presently set forth. On the inner periphery of the drum areblades 23, the outer ends of which are turned forwardly to form shovelsfor carrying the mixture up to the topof the drum and delivering same ina cascade, either through the body of the drum or into the deliverychute when the latter is projected into the drum.

Mounted on the frame 1, and inclosing the drum 2, is a super-structure25, and mounted on the super-structure at the inner end of-the drum is ahopper 26, the lower end of which carries a conduit 27 which isprojected through the opening 22 in the inner drum head, the end of theconduit terminatingl slightly within the drum open-y ing. Fixed to theend of the conduit is a plate 28 which is adapted for covering theopening 22 and extends slightly past the edges thereof, (Figs. III andIV). l

Mounted on the hopper 26 are standards 29 having a shaft 30 journaledtherein and provided with a sprocket wheel 31 over which a conveyer belt32 is adapted for travel so that buckets 33 may carry mineral aggregateup to and deliver same into the hopper. A sprocket Wheel 34 is fixed onthe shaft and driven from a belt 35 which may receive its power from anysuitable source, not shown, but preferably connected with the enginewhich is carried on the frame 1.

In the conduit 27 is a gate valve 36 whereby fiow fromthe hopper may becompletely stopped. Valve 36 is preferably operable from a rack 37,which extends horizontally past a pinion 38 on a vertical shaft 39journaled in bearings 40 on the frame 25 and provided with a hand-wheel41, whereby the rack may be operated to actuate the valve. A bracket 42is fixed on the frame 25 and braces the rack to hold same in properrelation to the pinion l38 to insure actuation of the rack and gatevalve when the shaft 39 is revolved.

The heater 3, which is Isupported on a frame 44 suspended from the truckframe 1, comprises a suitable `combustion chamber, preferably havingfire doors 45 at 'one end and adapted for burning fuel oil, a supplypipe 46 for the burner 46 being extended to and connected with the tank5.

At the rear of the heater'is a flue 47, preferably brick lined to nearits upper end, and having a nozzle 48 extending at an upward inclinethrough the plate 28 which lies over the opening 22 in the inner end ofthe mixing drum, so that heated air from the heater will be directedinwardly and upwardly toward the upper, outer corner\ of the drum.

The melting kettle 6, previously mentioned, may be of any suitable typeand is provided with a swiveling nozzle 50, having a hood 51 adapted tolie over a collar r 52'on the measuring tank 7, when the tank jacket 55around the sides and bottom thereof, the spacing being accomplished bymeans of a ring 56 which is projected between the receptacle and casingat the upper edges thereof and through which the rivets 57 areprojected, thereby serving not only as a spacer but also as a supportfor the inner receptacle, a head 58 being removably fixed on the ring 56to close the top of the tank, while affording access thereto. .In thehead 58 is an aperture 59, and fixed to the head, and registering withthe aperturev 58, is a collar 52 having ears 61 on opposite sidesthereof to which the saddle 62 and link 63 are pivotally connected.

A cap 64 is adapted to seat at the top of the collar 60 and a set screw65 is carried by the saddle 62 and adapted to bear against the cap 64 inorder to hold same firmly in place when the measuring tank is in use. Itis the collar 52 over which the hood 51 of' the swiveling nozzle on themelting kettle is adapted lto lie when the tank is to be filled.

Extending through the head 58 is a tube 67, the lower end of whichterminates near the bottom of the receptacle. Connected with the upperend of the tube 67 isa conduit 68 which extends to the inner end of themixing drum and Opens through the plate 28, the mouth ofthe conduitbeing located in the lower portion of the plate and directed downwardlyso that fluid asphalt, when discharged therethrough, will be so directedthrough the drum that whatever part of the fluid is carried entirelythrough the drum chamber will strike the\outer drum below the opening 19and thereby obvate loss of the material through the outer opening.

In order to prevent the asphalt from freezing during its travel throughthe conduit 68, I run a steam pipe 70 from thc boiler 4 into the upperend of the conduit and through the conduit to heat the measuring tank,so` that when steam is run through the pipe, asphalt is kept hot duringits travel through the conduit. The steam pipe 70 is run out of theconduit; adjacent the tank, and has a nozzle 71 opening into the side ofcollar 60, so that the steam may be delivered into the tank and providepressure for forcing fluid asphalt from the tank into the conduit andthence into the mixing drum, after first expanding in the feed collar.The exposed part'of the pipe is provided with a valve 72 and4 steam gage73- for cutting off the feeding supply and disclosing the steampressure.

On the pipe 7() is a branch 74 which opens into the space between theasphalt receptacle and casing to provide the steam jacket, and in thebottom of the casing is an exhaust nozzle which formsa free outlet forthe steam jacket in order that there may be a continuous flow of livesteam through the jacket 4to warm the tank and keep the asphalt thereinin a iuid state.

The delivery chute' which I prefer to use as part of the apparatuscomprises atroughlike member having hanger links 76 fixed thereto atabout the center, the links being bent to 'form crank-like members whichallow for the projection of the inner end of the trough into the drum toa greater extent than if said links were straight.

The upper ends of the .links are fixed on a shaft 77 which is revolublymounted in brackets 78 on the fram 25, and pivotally mounted on one ofthe lin (s above the drum opening is a latch 79 which is adapted forautomatic engagement with a hook 80 on the frame 25 when the conduit isin its active position, in order to hold said chute against accidentaldisplacement while the drum is being emptied.

Fixed to the outer end of the chute are links Sl the upper ends of whichare pivotally mounted on a shaft 82, also carried by the Frame, thedouble or concentric mounting of the chute facilitating the properprojection thereof into the drum.

Also fixed on the shaft 77, which carries the center hanger links, is abell crank lever 84, having a weight 85 at one end and a link 8Gconnected therewithiat the opposite end, the link 86 being adjiistablyconnected with a lever 87, which is adapted for travel over a quadrant88 on the frame 25 and whereby the delivery chute may be manipulated byan operator standing on the platform 89 on the frame 25;

In using the apparatus, presuming the parts to be constructed 'andassembled as described, a proper amount of mineral aggregate isdelivered to the hopper 26 through the conveyer and at the proper timedelivered from the hopper into the drumA by opening the gate valve 3Gand allowing the aggregate to drop through the conduit 27 into the drum.As the drum is in constant revolution when the apparatus is in use, theblades thereof piek up the mineral aggregate, carry same to an upperposition in the drum and deliver it in a cascade through the center ofthe drum chamber, thereby effecting a thorough mixture of the aggregate.While the drum is in revolution,

and the aggregatev being cascaded, as lde-` scribed, hot air from theheater 3 is delivered up through the flue 47,-18 and at an upwardincline through the drum chamber, the blast passing through the cascadeof mineral aggregate and heating and drying same thoroughly, the lastimpinging against the upper portion of the outer drum head, and beingdeflected backwardly into the chamber in order that the heated air maynot escape through the outer head opening until it has circulatedthrough the drum and absorbed a maximum amount of moisture. When thedrum is charged with the mineral aggregate, the measuring tank 7 isfilled with {iuid asphalt from the melting kettle 6, by opening thecollar 52 and lowering the swiveled nozzle 50 to bring the hood 51 overthe cap and allow asphalt from the melter to flow by gravity into thetank. As soon as the tank is full, the nozzle is again lifted and thecap 63 screwed onto the collar to firmly close the latter. The valve 72on the steam pipe is then opened to admit steam to the top of thereceptacle, the pressure from which forces the contents of the tank upthrough the tube 67 and conduit 68, from which it is delivered as a jetinto the drum and mixed with the minerall aggregate. The downwardincline of the jet mouth directs the lflow of asphalt downwardly andoutwardly through the cascade so that any material which may be thrownentirely thrugh the drum will strike against the outer head and fallback into the drum chamber and mix with the mineral aggregate instead ofescaping` through the opening in thehea-d.

As the jet of asphalt passes through the material cascading in the drum,it is mixed therewith so that when the combination falls to the bottomof the drum it is carried up by the blades and the entire mass cascadedto thoroughly mix the asphalt and mineral aggregate.

Under ordinary conditions, a pressure of twenty-five pounds in themeasuring tank will throw the jet of asphalt entirely through thecascade, and, in order to secure a proper mixture throughout the entirefall of mineral aggregate, the pressure may be regulated by the valve72, it having been found from experience that with a measuring tankcontaining fifty-two gallons and a two-inch conduit, twenty pounds ofsteam will force the liquid asphalt to about the center of the drum, andfifteen pounds will carry it only a short distance into the drum. liymanipulating the valve to vary the pressure between fifteen andtwenty-live `pounds a thorough mixture may be secured.

When the mixing operation is completed, the steam valve 72, andthemineral aggregate valve 36, are closed and the chute' 20 rocked" toproject its inner end intothe drum` so that the mixture dropping fromthe top of the drum will be delivered in the chute and therethrough intoa wagon, or other receptacle.

While the batch is being mixed, the hopper is filled with a new supplyof mineral aggregate, so that as soon as the drum is emptied and thechute removed a new charge may be delivered into th'e drum and theoperation described repeated.

If for any cause it should be impossible to empty the drum immediatelyafter the mixture has been completed, the `blast of hot air may be cutoff to obviate over-heating the mixture, and, if desired, the drum maybe stopped. If the batch should remain in the drum for sometime it isdesirable to reheat the mixture in the drum before withdrawing sametherefrom, in order that the material may be in proper condition to layon a street. y

It is apparent that with an apparatus of this description, not 0nly\ maythe mineral aggregate be thoroughly dried before receiving theaggregate, but the entire batch is dried in the mixer, thereby removingany moisture which may have been carried in from the steam used forforcing the Huid asphalt from the `measuring tank to the mixing drum.

It is also apparent that by injecting the asphalt into a shower of hotmineral aggregate, and eliminating flame from the drum, the asphalt istaken up and absorbed by the aggregate, and explosions in the mixerobviated.

Having thus described my invention, what I claim as new therein anddesire to secure by Letters-Patent, is

1. The method of mixing asphalt consisting of delivering a jet of fluidbinder through a cascade of mineral aggregate and varying thepenetration of the jet to deliver the binder at different points in thecascade.

2. The method of mixing asphalt consisting of applying pressure tobinder in a closed receptacle, forcing same under pressure through aconduit into mineral aggregate, and varying the pressure to vary thepenetration of the ud through the mineral aggregate.

In testimony whereof I affix my signature 1n presence of two Witnesses.

JOHN H. BLEDSOE.

Witnesses:

ARTHUR W. CAPS, LETA E. CoATs.

